Issues Related to the Use of Blood in Food and Animal Feed

Drying methods of duck blood: Changes in volatile components and physicochemical properties

This study investigated the physicochemical properties and volatile components of duck blood powder to determine its quality characteristics based on drying methods. The drying methods of duck blood samples used were freeze drying (FD), hot air drying (HD), spray drying (SD), and vacuum drying (VD). Duck blood powder treated with HD presented the lowest lightness and the highest carbonyl content. The VD-treated powder exhibited the highest water activity and redness. The composition of volatile compounds in duck blood varied based on the drying method, with VD presenting the highest total relative concentration but the least number of identified compounds. The most abundant compound was d-limonene, which was found in all the samples, followed by hexanal in VD and SD, p-xylene in FD, and trimethylamine in HD. Principal component analysis and heatmap analysis demonstrated that duck blood samples processed using different drying methods exhibited distinct volatile compound profiles, with HD, FD, SD, and VD samples associated with specific chemical groups. Multiple factor analysis revealed distinct correlations between drying methods and the physicochemical properties of duck blood, with VD samples showing higher water activity, aldehydes, and ketones, whereas HD samples exhibited increased carbonyl content and acids, highlighting the influence of heat on protein oxidation. VD method, therefore, presents excellent characteristics in terms of time and quality during the powdering process to increase the industrial utilization of duck blood. These findings provide valuable insights for the food industry, enabling the selection of appropriate drying methods that preserve the desired qualities of duck blood, thereby enhancing its commercial viability and potential application in a variety of food products.

Improved nutritional and antioxidant properties of black soldier fly larvae reared on spent coffee grounds and blood meal by-products

Black Soldier Fly larvae (BSFL) are a promising and sustainable alternative to obtain proteins. Due to their high growth rate and ability to use different substrates as feeding stocks, BSFL can be also used to valorize food waste. Thus, the aim of this research was to unravel the potential use of Spent Coffee Grounds (SCG) and blood meal alone or mixed as feedstocks for BSFL and the nutritional changes for BSFL meal, especially after simulated human in vitro digestion and fermentation. Chicken feed was used as a control. Chicken feed showed the highest BSFL growth (P < 0.05) compared with blood meal and the mix made of blood meal and SCG; the latter caused the lowest growth. The meal obtained from BSFL fed with blood meal had the highest protein content, as well as the highest levels of short chain fatty acids (SCFAs) produced after in vitro fermentation by the human gut microbiota. On the other hand, the meal from larvae fed with SCG showed higher antioxidant capacity than the others in the DPPH, FRAP and ABTS assays. The digestibility of macronutrients, release of antioxidant capacity and production of SCFAs of the BSFL meal were improved when using these substrates, compared to chicken feed.

Deer Blood Hydrolysate Protects against D-Galactose-Induced Premature Ovarian Failure in Mice by Inhibiting Oxidative Stress and Apoptosis

BACKGROUND

Premature ovarian failure (POF) is a common disease among women, which can cause many complications and seriously threaten women's physical and mental health. Currently, hormone replacement therapy is the primary treatment for premature ovarian failure. However, the side effects are serious and will increase the chance of breast cancer and endometrial cancer. Deer blood hydrolysate (DBH) is the product of enzymatic hydrolysis of deer blood, has antioxidant, anti-ageing, and anti-fatigue effects, and has the potential to improve premature ovarian failure.

METHODS

In our experiment, a mouse model of premature ovarian failure was established through intraperitoneal injection of 400 mg/kg/d of D-gal for 42 days. At the same time, different doses of DBH were gavaged to observe its ameliorative effect on premature ovarian failure.

RESULTS

The experimental findings indicated that DBH could restore the irregular oestrus cycle of POF mice, improve the abnormal amounts in serum hormones follicle-stimulating hormone (FSH), luteinising hormone (LH), progesterone (P) and estradiol (E2), increase the number of primordial follicles and decrease the number of atretic follicles. In addition, DBH also raised the level of superoxide dismutase (SOD) and reduced the level of malondialdehyde (MDA) and reduced the apoptosis of ovarian granulosa cells in mice. The WB assay results showed that gavage of DBH restored the decrease in the indication of nuclear factor erythroid 2-related factor 2 (Nrf2), Heme Oxygenase-1 (Ho-1), and B-cell lymphoma-2 (Bcl-2) proteins and reduced the elevated expression of Kelch-like ECH-associated protein 1 (Keap1), Bcl-2 associated X protein (Bax), and Cysteinyl aspartate specific proteinase-3 (Caspase-3) proteins that were induced by D-gal.

CONCLUSIONS

To sum up, the present research indicated that DBH can ameliorate D-gal-induced oxidative stress and apoptosis by regulating the Nrf2/HO-1 signalling pathway and the Bcl-2/Bax/caspase-3 apoptosis pathway, which can be used for further development as a nutraceutical product to improve premature ovarian failure.

Effects of konjac glucomannan as a freeze-denaturation inhibitor or binder on the physiochemical properties of heat-induced gel of freeze-dried duck blood

During freeze-drying, the degradation or eutectic melting of duck blood proteins can reduce the quality of duck blood gels. However, the interaction between proteins and polysaccharides during drying can improve protein-based gel quality. Therefore, here, we investigated the physicochemical properties of heat-induced gels of freeze-dried duck blood (FDB) and FDB with different proportions of the polysaccharide konjac glucomannan (KG), which serves as a freeze-denaturation inhibitor agent (FDA) or binder (BG). The pH and water-holding capacity (WHC) of FDB + KG gels were higher than those of FDB gel without KG (control). Especially, the WHC increased from 11.00% for control to 55.65% for FDB gel with 1% KG as a BG. Consequently, cooking loss and texture parameters of FDB + KG gels decreased. The hardness of control was 2.14 kg, which significantly reduced to 0.12-0.87 kg with KG addition. The highest carbonyl content was observed in control gel, and the thiobarbituric acid reactive substance content was reduced by the addition of 1% KG as an FDA (T1) or 0.8% KG as an FDA with 0.2% KG as a BG (T2) (p < 0.05). These changes might be induced by the alteration of tertiary structure and thermodynamic stability of gels. In conclusion, 1% KG can be used as an FDA to improve the quality and physicochemical properties of heat-induced gels of FDB. Optimized FDB gels with KG can be used as an innovative food ingredient to fortify nutrition and develop special dietary purposes.

Comprehensive Comparison of Bioactive N-Glycans among Seven Species of Livestock and Poultry Plasma Using a Relative Quantification Strategy

Glycans have been proven to play special roles in keeping human health as a class of nutritional and bioactive ingredients in many food materials. However, their broad use in the food industry is hindered by the lack of comprehensive analytical methods for high-quality food glycomics studies and large-quantity raw materials for their production. This study focuses on structural identification and quantitative comparison of bioactive N-glycans in seven species of livestock and poultry plasma as potential natural glycan resources by a novel comprehensive relative quantification strategy based on stable isotope labeling with nondeuterated and deuterated 4-methyl-1-(2-hydrazino-2-oxoethyl)-pyridinium bromide (d0/d7-HMP) in combination with linkage-specific derivatization of sialic acid residues. Methodological validation of the method in terms of detection sensitivity, signal resolution, quantification linearity, precision, and accuracy on model neutral and complicated sialylated glycans demonstrated its advantages over the existing methods. Based on this method, a series of bioactive N-glycans were found in seven species of livestock and poultry plasma, and their differences in structure, abundance percentages, and relative contents of N-glycans were revealed, demonstrating their excellent applicability for comprehensive food glycomics analysis and great exploitation potential of these plasma samples as large-quantity raw materials in producing bioactive N-glycans for application in food and pharmaceutical industries.

Toward the high-efficient utilization of poultry blood: Insights into functionality, bioactivity and functional components

A large amount of poultry blood is annually generated, and currently underutilized or largely disposed of as waste, resulting in environmental pollution and waste of protein resources. As one of the main by-products during the poultry slaughter process, the produced poultry blood can serve as a promising food ingredient due to its excellent functional properties and abundant source of essential amino acids, bioactive peptides and functional components. This work provides a comprehensive summary of recent research progress in the composition, functional and bioactive properties, as well as the functional components of poultry blood. Furthermore, the main preparation methods of poultry blood-derived peptides and their bioactivities were reviewed. In addition, their potential applications in the food industry were discussed. Overall, poultry blood is characterized by excellent functionalities, including solubility, gelation, foaming, and emulsifying properties. The major preparation methods for poultry blood-derived peptides include enzymatic hydrolysis, ultrasound-assisted enzymatic methods, macroporous adsorbent resins, and subcritical water hydrolysis. Poultry blood-derived peptides exhibit diverse bioactivities. Their metallic off-flavors and bitterness can be improved by exopeptidase treatment, Maillard reaction, and plastein reaction. In addition, poultry blood is also abundant in functional components such as hemoglobin, superoxide dismutase, immunoglobulin, and thrombin.

A critical review on slaughterhouse waste management and framing sustainable practices in managing slaughterhouse waste in India

Global meat consumption is on a rise with around 253 million metric tons of meat produced globally in the year 2020. Because of the rise in population and change in food preferences, meat consumption trend is likely to continue. Meat production by animal slaughtering increases the slaughterhouse wastes in the form of both solid and liquid wastes. Although various technologies for slaughterhouse waste management are available in developed countries, the effective utilization of slaughterhouse waste management is still missing in developing countries like India. India plays an active role in the meat export business globally and stood 2nd in the world with a total export valuation of 2.89 billion US $ in the year 2020. In this context, this study presents a critical overview of the current technological advancements in the global slaughterhouse waste management including utilization of by-products and further, the prevailing slaughterhouse waste management of India is discussed. Finally, a sustainable slaughterhouse waste management strategy emphasizing circular economy and regulations improvements have been suggested for India to compete in this sector at global scale.

Comparison of Functional Properties of Blood Plasma Collected from Black Goat and Hanwoo Cattle

Slaughterhouse blood is a by-product of animal slaughter that can be a good source of animal protein. This research purposed to examine the functional qualities of the blood plasma from Hanwoo cattle, black goat, and their hydrolysates. Part of the plasma was hydrolyzed with proteolytic enzymes (Bacillus protease, papain, thermolysin, elastase, and α-chymotrypsin) to yield bioactive peptides under optimum conditions. The levels of hydrolysates were evaluated by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The antioxidant, metal-chelating, and angiotensin I-converting enzyme (ACE) inhibitory properties of intact blood plasma and selected hydrolysates were investigated. Accordingly, two plasma hydrolysates by protease (pH 6.5/55°C/3 h) and thermolysin (pH 7.5/37°C/3-6 h) were selected for analysis of their functional properties. In the oil model system, only goat blood plasma had lower levels of thiobarbituric acid reactive substances than the control. The diphenyl picrylhydrazyl radical scavenging activity was higher in cattle and goat plasma than in proteolytic hydrolysates. Ironchelating activities increased after proteolytic degradation except for protease-treated cattle blood. Copper-chelating activity was excellent in all test samples except for the original bovine plasma. As for ACE inhibition, only non-hydrolyzed goat plasma and its hydrolysates by thermolysin showed ACE inhibitory activity (9.86±5.03% and 21.77±3.74%). In conclusion, goat plasma without hydrolyzation and its hydrolysates can be a good source of bioactive compounds with functional characteristics, whereas cattle plasma has a relatively low value. Further studies on the molecular structure of these compounds are needed with more suitable enzyme combinations.

Study on antioxidant activity of chicken plasma protein hydrolysates

This study optimised the hydrolysis process of chicken plasma protein and explored the in vivo antioxidant activity of its hydrolysates. The results showed that alkaline protease provided the highest degree of hydrolysis (19.30%), the best antioxidant effect in vitro. The optimal hydrolysis process of alkaline protease was: temperature 50 °C, time 8 h, [E]/[S] 7000 U g−1, pH 7.5. Antioxidant studies in vivo showed that the low, medium, and high dose groups significantly reduced the serum MDA and protein carbonyl content (P < 0.05) and significantly increased the serum SOD and GSH contents (P < 0.05). The results of HE staining of the liver showed that the liver cells in the model group were severely damaged, but the chicken plasma protein hydrolysates could alleviate this pathological damage. Chicken plasma protein hydrolysis products had certain antioxidant activity.

Effect of Drying Methods on Physicochemical Characteristics and Functional Properties of Duck Blood Gel

The drying of duck blood provides safety and commercial benefits, but each drying method has its own characteristics. Moreover, information on the effects of diverse drying methods on the quality of duck blood is limited. This study aimed to investigate the effects of various drying methods on the chemical and functional properties of duck blood. The physicochemical characteristics and functional properties of duck blood subjected to spray drying (SD), freeze drying (FD), vacuum drying (VD), and hot air drying (HD) were examined. The carbonyl content of FD duck blood powder was the lowest and the thermal stability was higher than that of the other treatments (p<0.05). The gel obtained from spray-dried blood displayed the lowest malondialdehyde content. The hardness, gumminess, and chewiness were the highest in the heat-induced gel prepared from FD duck blood powder (p<0.05). The gel obtained from FD duck blood displayed a denser structure than the other gel samples. Taken together, the FD duck blood exhibited excellent chemical properties and processing suitability.

Influence of Methylation and Polymerization on Flocculant Properties of Bovine Blood

Flocculants are used in the primary step of wastewater treatment to precipitate solids. Bovine blood is a slaughterhouse byproduct, and there is limited evidence in the literature demonstrating that it can be used as a flocculant. In this study, native bovine blood (NBB) and three types of chemically modified blood (methylated bovine blood (MeBB), polymerized bovine blood (PolyBB), and polymerized & methylated bovine blood (PMBB)) were tested against suspensions of negatively charged kaolin or positively charged hematite. The methylation reaction had the expected effect of increasing the apparent isoelectric point of MeBB and PMBB relative to that of the NBB starting material, and the polymerization reaction had the intended effect of increasing the average molar mass. NBB and PolyBB performed well with kaolin suspensions at pH ≤5.5, and MeBB showed high and consistent performance, across the pH range of 4.5-8.5. Relative to NBB, MeBB had improved potency and pH independence but also the disadvantage of increased sensitivity to overdosing. The performance of PolyBB was very similar to that of NBB. PMBB had performance enhancements similar to those of MeBB, with a modest improvement in its overdose sensitivity. The performances of MeBB and PMBB with hematite suspensions were poor at all tested doses (2-100 mg/g hematite), whereas a 30 mg/g dose of PolyBB showed 81% precipitation in an hour. The results show that simple chemical treatments can improve the utility of blood as a flocculant for negatively charged solids.

Anti-Fatigue Peptides from the Enzymatic Hydrolysates of Cervus elaphus Blood

Red deer (Cervus elaphus) blood is widely used as a health product. Mixed culture fermentation improves the flavor and bioavailability of deer blood (DB), and both DB and its enzymatic hydrolysates exhibit anti-fatigue activities in vivo. To elucidate the bioactive ingredients, enzymatic hydrolysates were fractioned into different peptide groups using reversed phase resin chromatography, and then evaluated using an exhaustive swimming mice model to assess swimming time and biochemical parameters. The structures of the bioactive peptides were elucidated by high performance liquid chromatography with tandem mass detection. Thirty-one compounds were identified as glutamine or branched-chain amino acids containing short peptides, of which Val-Ala-Asn, Val-Val-Ser-Ala, Leu(Ile)-Leu(Ile)-Val-Thr, Pro-His-Pro-Thr-Thr, Glu-Val-Ala-Phe and Val-Leu(Ile)-Asp-Ala-Phe are new peptides. The fractions containing glutamine or valine short peptides, Ala-Gln, Val-Gln, Val-Val-Ser-Ala, Val-Leu(Ile)-Ser improved exercise endurance by increasing hepatic glycogen (HG) storage. The peptides group containing Leu(Ile)-Leu(Ile), Asp-Gln, Phe- Leu(Ile), Val-Val-Tyr-Pro contributed to decreased muscle lactic acid (MLA)accumulation and to an increase in HG. The anti-fatigue activities of DB hydrolysates were attributed to the synergistic effects of different types of peptides.

Biogas production from slaughterhouse waste: Effect of blood content and fat saponification

The effect of fat saponification and the inclusion or exclusion of blood in slaughterhouse mixtures were assessed in terms of anaerobic digestion performance. Mixtures of animal by-products (ABP) were collected for 1 year, whereby following the daily activity and waste generation at a slaughterhouse facility, seasonal fluctuations were found. The blood content of ABP mixtures was variable, affecting both the methane yield and the production rate (287.8-320.5 NL_CH4 kg_COD^-1 and 80.3-94.7 and NL_CH4 kg_COD^-1 d^-1, respectively). The saponification of fatty ABP materials was studied to assess the methane production rate, singularly or combined, with and without the addition of blood. Data showed that saponification significantly reduced the lag phase, from 2.2 to 1.5 days in winter mixtures and from 1.5 to 0.9 days in summer mixtures (all with blood), and from 0.3 to 0.1 days in summer mixtures without blood. Finally, the percentage of energy demand at the slaughterhouse potentially covered by net biogas energy was estimated, finding that the facility could be 100% energy self-sufficient in winter, whereas this would be reduced to 85% in the summer due to different methane yields of ABP mixtures based on season.

Management of meat by- and co-products for an improved meat processing sustainability

Large amounts of meat by- and co-products are generated during slaughtering and meat processing, and require rational management of these products for an ecological disposal. Efficient solutions are very important for sustainability and innovative developments create high added-value from meat by-products with the least environmental impact, handling and disposal costs, in its transition to bioeconomy. Some proteins have relevant technological uses for gelation, foaming and emulsification while protein hydrolyzates may contribute to a better digestibility and palatability. Protein hydrolysis generate added-value products such as bioactive peptides with relevant physiological effects of interest for applications in the food, pet food, pharmaceutical and cosmetics industry. Inedible fats are increasingly used as raw material for the generation of biodiesel. Other applications are focused on the development of new biodegradable plastics that can constitute an alternative to petroleum-based plastics. This manuscript presents the latest developments for adding value to meat by- and co-products and discusses opportunities for making meat production and processing more sustainable.

Hemin from porcine blood effectively stabilized color appearance and odor of prepared pork chops upon repeated freeze-thaw cycles

This study was designed to evaluate changes in color following pork chop supplementation with porcine hemin, astaxanthin and paprika red in response to repeated freeze-thaw processes. Surface color analyses revealed that hemin significantly enhanced the appearance of the pork chops (P < 0.05), and the coloring efficiency of 0.10% hemin was similar to that of 0.20% astaxanthin and 0.08% paprika red. Sensory evaluations conducted on both raw and fried chops showed that hemin and astaxanthin significantly enhanced the overall acceptability of the chops before and after cooking. The color stability of the pork chops was also evaluated, and the results suggested that the hemin-colored chops were the most stable among the three, upon repeated freeze-thaw cycles. The electronic nose showed that the odor of the hemin-colored samples after 0, 3, and 7 freeze-thaw cycles was better than that of the other two groups. In conclusion, hemin may be a superior supplement for the large scale preparation of prepared pork chop.

Biotechnological Processing of Laying Hen Paw Collagen into Gelatins

By-products of laying hens represent a promising raw material source with a high collagen content, which is currently not adequately used. The aim of the paper is to prepare gelatins from laying hen paws. The purified collagen raw material was processed by a biotechnological process using the food endoprotease Protamex®. After cleavage of the cross-links in the collagen structure, the gelatin was extracted by a batch process with a stirrer in two extraction steps. The influence of the extraction process on the yield of gelatins and on selected qualitative parameters of gelatins was monitored by two-level factor experiments with three selected process factors. The studied factors were: enzyme dosage (0.2–0.8%), enzyme processing time (24–72 h) and gelatin extraction time (30–120 min). After the first extraction step at 75 °C, gelatin was extracted with a yield of 8.2–21.4% and a gel strength of 275–380 Bloom. In the second extraction step at 80–100 °C, it is possible to obtain another portion (3.3–7.7%) of gelatin with a gel strength of 185–273 Bloom. Total extraction efficiency of gelatins prepared from laying hen collagen is almost 30%. The prepared gelatins are of high quality and, under proper extraction conditions, gelatins with a gel strength above 300 Bloom can be prepared, thus equaling commercial beef and pork gelatins of the highest quality. Biotechnological processing of laying hen collagen into gelatins is environmentally friendly.

The performance of emerging materials derived from waste organism blood and saponified modified orange peel for immobilization of available Cd in soil

Waste organism blood (WOB) and orange peel are emerging stabilization materials obtained as by-products from agricultural processes, which are quite suitable for heavy metal immobilization in soil. In this work, waste organism blood and chemically modified orange peel (SOP) were investigated as potential sorbents for immobilization of available Cd in soil. Application of 5% WOB and SOP effectively immobilized cadmium (Cd) with an associated regulation of soil pH, among which the pH of acidic soil increased most significantly. While the application of 3% SOP alone stabilized almost the same amount of available Cd compared to WOB, it caused the highest stabilization rate of 58.85% when applied at 5%. By contrast, SOP combined with WOB (the mass ratio of the material is 1 : 1) at a 5% addition rate stabilized the available Cd in soils remarkably, with a stabilization rate of 57.74%. This study revealed that the soil particles after stabilization have a more compact and flaky structure, and the SOP and WOB had a particular pore structure, which was helpful for the adsorption of available Cd in soil. This study put forward new insights into the potential effects of Cd immobilization in contaminated soil by newly emerging stabilization biomass materials (WOB and SOP).

Detection of porcine pepsin in model cheese using polyclonal antibody-based ELISA

The usage of porcine pepsin or other porcine derivatives in food products is a common practice in European, American and certain Asian countries although it creates issues in religious and personnel health concerns. In this study, porcine pepsin was detected using indirect ELISA that involved the anti-pep80510 polyclonal antibody raised against a specific peptide of porcine pepsin, pep80510. The sensitivity of the assay for standard porcine pepsin was 0.008 µg/g. The immunoassay did not cross-react to other animal rennet and milk proteins except for microbial coagulant from Mucor miehie. The recovery of porcine pepsin in spiked cheese curd within the range of CV < 20% while for porcine pepsin in spiked cheese whey the recovery is also within the range of CV% < 20%.

Chicken Heads as a Promising By-Product for Preparation of Food Gelatins

Every year, the poultry industry produces a large number of by-products such as chicken heads containing a considerable proportion of proteins, particularly collagen. To prepare gelatin is one of the possibilities to advantageously utilize these by-products as raw materials. The aim of the paper was to process chicken heads into gelatins. An innovative method for conditioning starting raw material was using the proteolytic enzyme. Three technological factors influencing the yield and properties of extracted gelatins were monitored including the amount of enzyme used in the conditioning of the raw material (0.4% and 1.6%), the time of the conditioning (18 and 48 h), and the first gelatin extraction time (1 and 4 h). The gelatin yield was between 20% and 36%. The gelatin gel strength ranged from 113 to 355 Bloom. The viscosity of the gelatin solution was determined between 1.4 and 9.5 mPa.s. The content of inorganic solids varied from 2.3% to 3.9% and the melting point of the gelatin gel was recorded between 34.5 and 42.2 °C. This study has shown that gelatin obtained from chicken heads has a promising potential with diverse possible applications in the food industry, pharmacy, and cosmetics.

Effect of different time of ultrasound treatment on physicochemical, thermal, and antioxidant properties of chicken plasma protein

The aim of present study was to investigate the effect of different times (5 min (UCPP-5), 10 min (UCPP-10), 20 min (UCPP-20), and 30 min (UCPP-30)) of ultrasound treatment on physicochemical, thermal, and antioxidant properties of chicken plasma protein (CPP). UCPP-20 had the highest fluorescence intensity and the lowest particle size. However, no major changes in the subunit compositions and the secondary structure of UCPPs were presented in SDS-PAGE and circular dichroism. The surface hydrophobicity and sulfhydryl content of UCPPs increased significantly (P < 0.05) as compared to those of CPP. With the increasing time of ultrasound treatment, there were more and deeper holes on the protein surfaces. Furthermore, protein modification by ultrasound could improve the thermal properties of UCPPs. Additionally, UCPPs showed a significant increase in antioxidant properties over CPP, especially UCPP-20. These observations indicated that ultrasound treatment was necessary for modification of CPP to meet the requirements for food processing.

Novel technologies in utilization of byproducts of animal food processing: a review

China is one of the countries with most abundant livestock and poultry resources in the world. The average annual growth rate of output value of livestock and poultry industry reaches 13%, and the output value of livestock and poultry industry accounts for more than 35% of total agricultural output. A large number of byproducts are produced in animal slaughtering and processing operations. If livestock and poultry byproducts are effectively utilized, this will make a huge contribution to GDP. At the same time, aquaculture is China's pillar industry. During fish processing, a large number of byproducts (including fish heads, fish skins, fish bones, fish scales, and viscera) are produced, which weighs approximately 40-55% of the raw fish. The byproducts of freshwater fish are more than 2.5 million tons per annum, most of which are not used. The effective use of byproducts has a direct influence on China's economic and environmental pollution. The nonuse or underutilization of byproducts not only leads to loss of potential revenue, but also results in to an increase in these products and their disposal costs. This paper makes a comprehensive review of the research progress of animal byproduct utilization to date, and aims to provide reference for the utilization and research of animal byproducts.

Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain

There is a growing market for the use of hydrolysates from animal side-streams for production of high-protein supplements. However, there can be issues with development of off-flavors, either due to the raw material in question or due to the hydrolysis process itself. This study examined the development of volatile compounds during hydrolysis of hemoglobin. Briefly, porcine hemoglobin was hydrolyzed by 0.5% papain for up to 5 h, and the development of volatile compounds was analyzed via gas chromatography-mass spectrometry. The results showed that there was significant development of a number of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found in a control without enzyme.

Monoclonal antibody-based enzyme immunoassay for detection of porcine plasma in fish surimi

Detection of porcine plasma using indirect ELISA was developed using mAb B4E1 for the prevention of their usage in human food that creates religious and health conflicts. The immunoassay has a CV < 20% and did not cross-react to other meat and non-meat proteins. The sensitivity of the assay is 0.25% (w/w) of porcine plasma in spiked raw and cooked fish surimi. The assay did not produce a false positive result for any of the commercial fish surimi tested that were not contain porcine plasma. Determination of a 60-kDa antigenic protein of porcine blood using Western blot confirmed its presence in the plasma fraction of the porcine blood. Further proteomic analysis involving liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed the 60-kDa protein to be porcine serum albumin.

Comparative Study on Compositions and Functional Properties of Porcine, Chicken and Duck Blood

Hematological, chemical and functional characteristics of porcine, chicken and duck blood were evaluated. A porcine blood sample showed the most abundant red blood cell, hemoglobin concentration, packed cell volume and plasma protein content as well as its freeze-dried blood possessed the highest contents of protein, fat, Cu and Cr with the highest percentage of heme iron (p<0.05). Unlike porcine blood, chicken blood showed a well balance in some essential amino acids, specifically for a higher isoleucine content (p<0.05). Furthermore, it possessed the highest contents of carbohydrate, Zn and non-heme iron (p<0.05). The most rapid response to form a strong gel, especially at 70°C and 80°C, was found in chicken blood, followed by duck and porcine blood, respectively. The result of emulsion activity index (EAI) and emulsion stability index (ESI) at the low protein concentration indicated that chicken blood had the most superior emulsion properties (p<0.05). Regarding duck blood, it exhibited the highest content of Mg and Mn (p<0.05). Moreover, duck blood had similar foaming properties to porcine blood in which they showed higher values than chicken blood (p<0.05). Specific characteristics of blood were therefore diminished by animal species in which this information could be used as food supplementation or product development based on their potential applications.

New insights into meat by-product utilization

Meat industry generates large volumes of by-products like blood, bones, meat trimmings, skin, fatty tissues, horns, hoofs, feet, skull and viscera among others that are costly to be treated and disposed ecologically. These costs can be balanced through innovation to generate added value products that increase its profitability. Rendering results in feed ingredients for livestock, poultry and aquaculture as well as for pet foods. Energy valorization can be obtained through the thermochemical processing of meat and bone meal or the use of waste animal fats for the production of biodiesel. More recently, new applications have been reported like the production of polyhydroxyalkanoates as alternative to plastics produced from petroleum. Other interesting valorization strategies are based on the hydrolysis of by-products to obtain added value products like bioactive peptides with relevant physiological effects as antihypertensive, antioxidant, antidiabetic, antimicrobial, etc. with promising applications in the food, pharmaceutical and cosmetics industry. This paper reports and discusses the latest developments and trends in the use and valorisation of meat industry by-products.

Response surface optimization of enzymatic hydrolysis of duck blood corpuscle using commercial proteases

With the rapid development in livestock and poultry husbandry and increasing shortage of protein sources, recycling of wastes from agricultural and food processing such as blood corpuscles has been regarded as an important industrial procedure to obtain protein sources. This study aimed to find an appropriate method for recycling the considerable amounts of blood corpuscle so as to improve its nutritional value and organoleptic quality. An effective production process for enzymatic hydrolysis of duck blood corpuscle was successfully developed and optimized by response surface methodology. Optimal conditions based on achieving a high value of trichloroacetic acid solubility index were substrate concentration of 14 g/100 mL, temperature 51°C, initial pH 7.0, and time 7.5 h. The electrophoretic patterns of the protein hydrolysate were investigated, and a large diffuse band was observed in the vicinity of 5 kDa. The organoleptic quality of spray-dried blood corpuscle hydrolysate was also evaluated, indicating that enzymatic hydrolysis and decoloration methods were feasible and cost-effective to achieve the desirable bright yellow product without bitterness. In vitro protein digestibility of blood corpuscle hydrolysate was 96.32 ± 0.50%, which was better than that of soybean, fish meal, and casein. Based on the amino acid composition and nutritional parameters, we found that the spray-dried blood corpuscle hydrolysate had abundant nutritional value and high potential for application as an ingredient in nonruminant animal feed.